PET is a functional imaging technique in nuclear medicine that produces a three-dimensional image of functional processes in a living object. Typically, a short-lived radioactive isotope tracer, such as fluorodeoxyglucose (FDG), may be injected into the object. The tracer may undergo a positron emission decay (also known as beta decay) and emit a positron. The positron may annihilate with an electron and a pair of annihilation photons (or gamma photons) that move in approximately opposite directions.
A PET system may include a PET detection module configured to detect the photons. Typically, the detection module includes a scintillator array, one or more optical detecting components such as PhotoMultiplier Tubes (PMT) or Silicon Photomultipliers (SIPM), and a post-processing circuit. However, each of the PMT tubes may need an individual power supply and hence may make the detection module complex and unstable. SIPM may not require the individual power supply, but each of the SIPM may be connected to a scintillation crystal of the scintillator array and a post-processing circuit. Based on this arrangement, the number of SIPM and the post-processing circuit may have to be increased if the number of scintillation crystals increases. As a result, the size of the detection module is limited and the cost is high.